First Steps:

Analysis and Troubleshooting:

wWhat happened?
wWhen does the problem occur?
wDocument everything you were doing just before the problem occured.
wPrintout or write down exactly all error messages.
wDoes the problem predictably reoccur?

Usefull Tips:

Do Not click on any links if you receive a pop-up window with the alert "We have detected critical errors in your Windows System, Click HERE to repair them." The malware that will be installed will hijack your computer and request that you to purchase their software in order to remove it and regain access to your system.

Amberdell Computer Technologies provides user support

Amberdell Computer Technologies provides links to Symantec support and advisories: